I don't want to add egg to bind hash browns. What is the best way to bind hash brown without the eggs?
My first thoughts are should I still grate the potato, or boil first to soften to enable them to bind?
I follow Alton Brown's recipe from Good Eats for grated (the only way!) hash browns and never have problems with it binding. It's from the episode "Another Man Food Show: Breakfast" if you want to search it out. He talks on the show about why the type of potato matters and recommends a high starch potato like an Idaho or Russet. I use Russets as they're readily available here and never have any issues.
Summary of the cooking process:
Try this really simple technique I discovered in a hash brown recipe once: Place grated potato into a bowl. Sprinkle salt over (about a teaspoon), mix salt through the potato and leave for a few minutes. Pick up handfuls of potato and squeeze excess moisture out until you've done all the potato.
The salt draws out the liquid. This seems to make the potato stick together really well.